Process of manganese ore treatment



Oct. 31, 1933. N. A. LAURY PROCESS OF MANGANESE ORE TREATMENT Filed July '29 1925` zoinw gf 2T 29h16@ *omni 1 v ZDC'DJow zQrSJom 6221 vzjooo womci ZOTPDJOW KMLHZK mmc OKl MEO l fOI ENT ortis D TATS PROCESS F MANGANESE GRE TREATMENT Napoleon `Arthur Laury, Rockville Center, NQY.,v

assigner, by mesne assignments, to Howard B. Bishop, Summit, N. J.

Application July 29, 1925. Serial No. 46,739

l0 Claims.. (Cl. 23--1/15) My invention relates to the recovery of mangaforms a soluble salt with the manganous oxide by vnese compounds from manganese bearing ores double decomposition, such for example, as `the and its primary object is to vprovide a process chloride or sulphate. The double decomposition whereby such compounds may b e efficiently proalsoV forms ammonia, which ordinarily would be duced from low grade manganese bearing ores expected to precipitate manganous hydroxide 60 containing say less than twenty per centum of from the solution. However, it is welllnown that manganese, of which large deposits exist, as well seine metals, including `manganese, are not preas from higher grade manganese bearing ores. cipitated as hydroxide lby ammonia when ain- I-Iaving actually carried out the new process of moniurn salts are also present. Physical chemismy invention, I am enabled to set itV forth in try attributes this face to the repression of the o5 this specification in considerable detail, and I ionization or" the ammonia to such a degree that v do so in order to teach those skilled in the art the hydroxyl ions are not sufficiently concenfully in its use, but I desire that itshall be undertrated to precipitate the manganese as the stoodv that details, though important and made lfiydroxide.v Under these conditions the ammonia the subject matter of the more limited of the apexists in the solution merely as dissolved am- 7o pended claims, may be varied and that the broadmoniuin hydroxide and it is quite ineffective upon er scope of my invention is to be 1measured by the the dissolved manganous salts. In order to rebroader ofthe appended claims. duce the aniountof ammonium salts required to Manganese exists in the ores with whichrI am hold the manganese in solution against precipitaconcerned, principally in its higher oxides, such tion by ammonia, the reaction of the ammonium 75 as manganese dioxide, and my process isk acsalts on the inanganous oxide is carried out uncordingly accommodated to that fact, but it is der conditions favorable to decreasing the alkaimportant that my process is effective in the linity. By this procedure the manganous oxide treatment of ores which contain manganese as may be rendered soluble Without danger of subcarbonates. sequent precipitation by the ammonia formed dur- 80 ,At the outset I grind the crude ore to nely ing the process of rendering the manganous oxide divided form (I have gone as far as two hundred soluble. The preferred manner of carrying out v mesh), and then heat it in a reducing furnace to the leaching process so as to reduce lthe alkalinity over six hundred degrees Centigrade for several is to remove the ammonia by conducting the prohours in the presence of a reducing agent, in excess at a temperature ensuring the escape of am- 85 cess, in the form of a gas, such as hydrogen, carmonia from the solution. The preferred leaching bon monoxide, or illuminating gas, or in solid solution Vis anrinoonium sulphate and the process form, such as free carbon o1` coal, mixed with it. is hereinafter described as carried out by the use i The purpose oi this reduction is to bring the manof ammonium sulphate.

gallese compound down to manganese monoxide; The leaching solution `isone of an ammonia 90 and as an example of the excess of reducing agent salt, such as ammonium sulphate or ammonium required, I point out that, for instance, where chloride, and I shall use ammonium sulphate as three and eight-tenths per centum of carbon is a specic example. l theoretically required for the reduction, veper Although the other oxides of manganese and 40 centum is sulicient. its -carbonates are not soluble in the ammonium 9-5 Reduction of the dioxide by hydrogen is as folsulphate solution, manganese `monoxide is, and loWs:- the reduced oreis introduced to this leaching rel\/InO2-[II2=MnO-II2O. Y agent and goes intofsolution, as follows2 The manganese in the ore having been reduced MnO-l- (NI-I4) 2SO4=MnSO4|2NH3lII2Q 100 to the monoxide, as just described, it is important leaving behind the Temandw of the Ore: which that the ore be cooled out of contact with the air is insoluble except some possible Soluble mmlp to prevent re-oxidization, and vthis may be eecties which] I have found are negligible gogh in tively accomplished by immediately quenching Character and quantity. 60 the hot Ore in Water 01': indeed in the leaching .i The strength oi the leaching solution is im- 105 Solution Which iS the 'eagelt in the next Stell portant, since there must be sulicient solution The leaching DIOCSSS iS bSed Upon the fact to insure the dissolving of all the manganese that manganous oxide obtained as above described Salt, manganous Sulphate in this' oase, in which Call be bIOllgh IllJO SOlutiOIl by the aCtOn 0f al a fifteen per centum solution of, ammonium sulsuitable ammonium salt, the acid-radical of which phate is preferably employed. The leaching is Y110 preferably aided by heat to a temperature of approximately eighty degrees centigrade, requiring several hours without, and a lesser time with, agitation. It is also preferable that the leaching be so conducted and controlled as to exhaust substantially all the ammonium sulphate in the solution, leaving only manganous sulphate. dissolved, since a considerable amount 01' ammonium sulphate remaining in the solution at the end of the leaching operation interferes with the further procedure in the process. It may be desirable to leach the ore in two stages, i. e., fresh ammonium sulphate solution may be used to treat partially leached ore (which may be finely ground) and partly converted solution may be used to treat fresh ore (which may be coarsely ground).

From the ioregcing it will be apparent that it is the escape of ammonia from the leaching operation that permits substantially all the ammonium salts to be changed to manganous salts. There being substantially little ammonium hydroxide left in the solution, there is required no free ammonium salts to hold the manganous salt in solution against precipitation by the ammonia.

In the above leaching reaction, as will be noted, ammonia gas is given oil and it is preferably recovered for further use-in the process, as follows:-

The manganous sulphate solution is then separated from the insoluble remainder of the ore by iiltering and is cooled, and, in cool condition, is treated with ammonia, resulting in the precipitation of manganous hydroxide and the restoration of ammonium sulphate solution. The ammonia released and recovered during the leaching operation may be passed directly to a cooling tower to meet, in counter current, the clear cool manganous sulphate solution, or it may be used to form aqueous ammonia which may then be added cool to the cool manganous sulphate solution. Aqueous ammonia testing approximately twenty-six degrees Baume is satisfactory for this purpose, the ammonia solution being added to the other with stirring until pink to phenol phthalein. The reaction is as follows:-

rihe precipitated manganous hydroxide, which is white, is then separated from the ammonium sulphate solution, by filtering or decanting, preferably protected from the atmosphere, and is then subjected to heat to a temperature or say up to about eight hundred and twenty iive degrees centigrade whereby it is dehydrated to substantially pure manganese monoxide, commercially a highly desirable form of manganese, as follows:-

material, however, because the solution is not discarded but is used over again for another leaching process, and any manganese which may be retained therein is subject to precipitation in the next cycle.Y

The use of the liberated ammonia and thev restoration of the ammonium sulphate solution, as above pointed out, makes the process of my invention regenerative and continuous, aswill be evident from the accompanying drawing. The drawing is purely diagrammatic and is fully supplied with nomenclature so that it speaks `for itself.

The tailings from the filter which separates the manganous sulphate solution irom the insoluble remains of the ore comprise, primarily, silica and iron as an oxide which is in magnetic form and may be concentrated for commercial purposes as a by-product.

claim:

1. The process of recovering a manganese compound from material containing manganous oxide, which comprises leaching the material with a solution of an ammonium salt capable of forming a soluble manganous salt, simultaneously removing the resulting ammonia from the leaching liquonand then precipitating a manganese compound from said solution by means of ammonia.

2. A cylic regenerative process for recovering a manganese compound from material containing manganous oxide which comprises, treating the material with a solution of an ammonium salt of an acid of which the manganous salt is soluble, simultaneously releasing the resulting ammonia from solution, conserving the ammonia, separating the manganous salt solution from the insolubles, precipitating manganese hydroxide from said solution by the conserved ammonia whereby to form regenerated ammonium salt, separating the hydroxide from the ammonium salt solution, and conserving the ammonium salt solution for subsequent leaching operations.

3. The process oi' recovering a manganese compound rorn material containing manganous oxide, which comprises leaching the material with a solution of an ammonium salt capable oi forming a soluble manganous salt, simultaneously treating the leaching liquor to release ammonia, and then precipitating a manganese compound from said solution by means or the ammonia released in said leaching operation.

4. The process of recovering a manganese compound from material containing manganous oxide, which comprises leaching the material with a solution of an ammonium salt capable of forming therewith a soluble manganous salt, simultaneously treating the solution to remove the resulting ammonia, then treating said manganous salt solution with ammonia to precipitate a manganese compound and form a solution oi said ammonium salt, and leaching fresh ore with rib said solution of said ammonium salt thus formed. Y

5. The process or" recovering manganese from ores, which comprises leaching a charge containing manganese monoxide with a solution Yof a salt of ammonia with an acid oi which the manganous salt kis soluble under the influence of heat whereby simultaneously to form a solution of a manganese salt and to release ammonia, and then cooling said solution and precipitating the manganese therefrom.

6, The process of recovering manganese from ores, which comprises leaching a charge containing manganese monoxide with a solution of a salt of ammonia withan acid o which the manganous salt is soluble under the influence of heat to a temperature of eighty degrees centigrade whereby simultaneously to form a solution of a manganese salt and to release ammonia,

ist

and then cooling said solution and precipitating the manganese therefrom.

7. Theprocess of recovering manganese monoxide, which comprises grinding a manganese bearing ore to a finely divided state, heating the' same in the presence of a reducing agent to reduce its manganese content to manganese monoxide, leaching the ore thus reduced with a soluv tion of an ammonium salt capable of interaction With the manganous oxide to form a manganous salt under the influence of heat whereby simultaneously to form a manganese salt solution and to release ammonia, recovering said ammonia, separating said manganese salt solution from the insolubles, cooling said manganese salt so-V lution and treating the same under cool conditions with the ammonia thus recovered to precipitate manga-nous hydroxide and form a solution of said ammonium salt, separating said manganous hydroxide from said solution of said ammonium salt, and leaching fresh reduced ore With said nal solution of ammonium salt.

8. The process of recovering a Ymanganese compound from material containing manganous oxide which comprises vleaching the material with a solution of an ammonium saltV capable of forming a soluble manganous salt, simultaneously removing the resulting ammonia from the leaching liquor, and then precipitating a manganese compound from said solution by means of said ammonia.

9. The process of recovering a manganese compound from material containing manganous oxide, which comprises leaching the material With a solution of an ammonium salt capable of forming therewith a soluble manganous salt, simultaneously treating the solution to remove the resulting ammonia, then treating said manganous salt solution with said ammonia to precipitate a manganese compound and form a solution of said ammonium salt, and leaching fresh reduced ore with said solution of said ammonium salt thus formed.

10. The process of recovering manganese monoxide Which comprises leaching a charge` containing the same with an ammonium sulphate solution under conditions simultaneously to form a inanganous sulphate solution and to release ammonia, treating said manganous sulphate solution with said ammonia to form manganous hydroxide and ammonium sulphate solution, and

then separating out said manganous hydroxide and dehydrating it to manganese monoxide.

` N. ARTHUR LAURY. 

